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What a year of solar and batteries saved us in 2025

scotthelme.co.uk

131–140 of 368 posts

Re: What a year of solar and batteries saved us in 2025

#131
post #79

Earlier quoted context omitted.

Surely it only needs to be signed off if you intend to sell the property with them or sell excess back to the grid. If youre just using the batteries how is anyone going to know?

If your house burns down for any reason, not necessarily the DYI batteries, the insurance company will know anyway.

If the DIY work wasn't the cause for the fire it shouldn't matter, but I half-expect someone to inform me that US insurance companies can (legally) deny coverage for reasons unrelated to the accident.

Re: What a year of solar and batteries saved us in 2025

#132
post #91

> The batteries can fill up on the off-peak rate overnight at £0.07/kWh, and then export it during the peak rate for £0.15/kWh, meaning any excess solar production or battery capacity can be exported for a reasonable amount. Honestly I didn't know this was allowed. I recently got a heat pump and am on a time-of-use tariff ( https://octopus.energy/smart/cosy-octopus/ ) and have been thinking about pulling the plug on…

Why wouldn't it be allowed? They're essentially renting their batteries and grids generally lack storage

Re: What a year of solar and batteries saved us in 2025

#133

> Having our full costs returned in ~11 years is definitely something we're happy with Except that after 11 years the equipment will have broken down or become obsolete, at which point you have to start over. > we've also had protection against several power outages in our area along the way, which is a very nice bonus. This seems to be the real benefit of the setup.

> Except that after 11 years the equipment will have broken down or be obsolete, at which point you have to start over.

If my calculations are correct, that setup probably lasts at least 30 years. This is not a cell phone battery and panels do not degrade that fast.

Re: What a year of solar and batteries saved us in 2025

#134
post #117
post #51

Earlier quoted context omitted.

Almost all simulations I've done across 3 countries with 3 different payback models for selling back to grid (one of the three doesn’t allow selling back almost anything above your consumption), I could never make investing in Solar not being a gamble. You really need to gamble on odds of replacing equipment being very low for it to make sense. And in practice most people I anecdotally know that run it, after 5-7 yea…

Having done 2 solar installs, one over 10 years and one 6 years, both going strong. Nothing else needed, it just sits there and produces. So, from my experience, that's not the case. Maybe the people you know keep tweaking because they're enthusiasts like you have with cars.

It could be as simple as a different model. In one of those it was easy to make it feasible if you had no cap on how much to sell back, but it was limited to consumption plus like 10% or something like that. Since the property used very little energy but had a big roof we thought itd be a good thing to produce green energy while making a little money or even just breaking even, but to break even we'd have to use way more energy which was completely against the original objective. So its not like the technology isn't able to do it but the rules can make it very hard and a few years less of operation for some components make the math very difficult if you're conservative and want to ensure break even within some reasonable timeline

Re: What a year of solar and batteries saved us in 2025

#135
post #52

It's wild how overpriced Tesla Powerwalls are. 16 kWh battery with all of the UL supported listings etc = $3300 [0] 13.5 kWh Tesla Powerwall is $12k~$15k You would get your return way back quicker. [0] - https://www.ruixubattery.com/product-page/lithi2-16-battery-... EDIT: As others have pointed out, powerwalls have inverters built in so it's not totally apples to apples. You can get a beefy inverter for $5k and it's…

That's not really apples-to-apples comparison. The Tesla batteries are AC coupled so they work with an (AC coupled) microinverter array. For a DC coupled battery you have to have a hybrid inverter and DC couple the batteries. Your point that they are overpriced still stands though.

Ya as someone else pointed out, powerwalls essentially have an inverter built in. But this is really dumb to have inverters tied directly to each powerwall battery. This is like anti-scale.

Re: What a year of solar and batteries saved us in 2025

#136

Earlier quoted context omitted.

You're comparing the cost of a battery with a full system. That 16 kWh battery requires a ~$3000 inverter to go along with it.

Well, the math still maths, right? I am writing this off grid, using about 15kwh of batteries and a $1200 (6kw) inverter. My entire system puls panels and racking those panels, plus wiring some un-powered shacks was about $10k, though I did the work myself (which would probably hae been another 3-5k if I could have found someone to do it.

> which would probably hae been another 3-5k if I could have found someone to do it.

Yo. If you can find an electrician to stop by my house and turn a light switch off for less than 1000$, please inform me. I got a quote for 25k$ to install a system that size, and that price. City code has me by the balls: I can't modify my main panel without inspection, the inspector won't show up without a licensed electrician, and electrician wants the labor. I pointed out that we're talking 8 hours of labor — call it 2500$, lawyer money — and he was like "what's your choice". I'm in Texas.

Re: What a year of solar and batteries saved us in 2025

#137
This is indeed nice for a well-to-do home. But there is a tragedy of the commons issue here.

The grid needs to be up 24/7. And while peak usage is just that, the grid capacity still needs to support peak usage.

This can theoretically be done using batteries but not for an extended amount of time. To say we can have batteries for 2 weeks of normal consumption is highly improbable.

The metals do build those batteries do not exist. Or put in a worse way, the mines do not exist.

An off the cuff calculation of costs and the massive amount of batteries required in the context of Sweden can be found (you need to translate) here: https://www.tn.se/naringsliv/40181/utrakning-60-globen-batte...

In other words, 60 full scale Globen arenas of batteries to replace current Swedish nuclear production.

So for small houses these investments can make sense currently. But from a larger perspective it's not that interesting.

Re: What a year of solar and batteries saved us in 2025

#138
post #128

> Having our full costs returned in ~11 years is definitely something we're happy with Except that after 11 years the equipment will have broken down or become obsolete, at which point you have to start over. > we've also had protection against several power outages in our area along the way, which is a very nice bonus. This seems to be the real benefit of the setup.

What breaks in 11 years? Solar panels and batteries both last longer than that. As for your other point of becoming obsolete, why care about chasing latest fads for home appliances.

Are you sure? Lots of people are telling me that batteries only last 4-5 years tops and solar panels usually burn out before 10 years /s

I particularly love when they are telling me that my 11 year old Prius' batteries will only last 5 years before they are junk.

Re: What a year of solar and batteries saved us in 2025

#139
The rooftop solar game in Texas is strongly into scam territory. Most homes I see with panels on the roof are two story homes where you have a negligible amount of area to work with relative to interior space. There was a point where you'd have to deal with a door-to-door salesman approximately every 48h for an entire summer.

The most realistic residential installation I've seen was firmly on the ground at a ~2 acre property. The panels were much larger and heavier (i.e., capable) than what you'd typically find on a roof. It's much easier to build and maintain a solar array when you don't need a ladder/crane to move things around.

I think that it's great that we want to participate in making things better, but not every situation makes sense. When you factor in all of the downstream consequences of sub-optimal, fly-by-night installs, it starts to look like a net negative on the environment. I'm not trying to claim that all rooftop solar projects are bad, but most of the residential ones I've seen make absolutely zero economic sense.

Large scale wind and solar projects are the best way forward. You get so much more bang for buck. I'd consider investing in these projects or their upstream suppliers and owners if you want to get involved financially in making the environment a better place.

Re: What a year of solar and batteries saved us in 2025

#140

Earlier quoted context omitted.

This is factually inaccurate. Solar PV panels will continue to produce power at 80-90% of rated output after 25 years, and battery storage will still have 80-90% capacity. I'm sure you can understand that as long as the system is storing and producing power at these levels, its value is not zero.

Can you point out what part of what I said is factually inaccurate?

https://magnifina.com/articles/rooftop-solar-yield/ explains it better than me attempting to write a wall of text.
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